The present invention relates generally to the field of hierarchical storage management systems, and more specifically to reducing the frequency of data recalls from a slower storage level to a faster storage level.
The Wikipedia entry for “Hierarchical storage management”, as of May 24, 2016, states as follows: “Hierarchical storage management (HSM) is a data storage technique, which automatically moves data between high-cost [primary] and low-cost [secondary] storage media. HSM systems exist because high-speed storage devices, such as hard disk drive arrays, are more expensive (per byte stored) than slower devices, such as optical discs and magnetic tape drives . . . . HSM systems store the bulk of [an] enterprise's data on slower devices, and then copy data to faster disk drives when needed. In effect, HSM turns the fast disk drives into caches for the slower mass storage devices. The HSM system monitors the way data is used and makes best guesses as to which data can safely be moved to slower devices and which data should stay on the fast devices.”